Due to the increasing demand for high data rates over wireless, there has been an accompanying increased interest in operation of LTE system in unlicensed frequency bands. The unlicensed frequency band of current interest in 3GPP is the 5 GHz band, which has wide spectrum with global common availability. The 5 GHz band is governed by Federal Communications Commission (FCC) in US and European Telecommunications Standards Institute (ETSI) in Europe. The main incumbent system in the 5 GHz band is the Wireless Local Area Networks (WLAN), specifically those based on the IEEE 802.11 a/n/ac technologies. Since WLAN systems are widely deployed both by individuals and operators for carrier-grade access service and data offloading, sufficient care must be taken before deployment to ensure co-existence.